Added worksheet_ignore_errors() function.

Added worksheet_ignore_errors() function to ignore Excel
worksheet errors/warnings in user defined ranges.

dev/release/fix_example_docs.pl

@@ -47,6 +47,7 @@ my @examples = (
     [ 'comments2.c',            'Example of adding cell comments with options' ],
     [ 'macro.c',                'Example of adding a VBA macro to a workbook' ],
     [ 'panes.c',                'Example of how to create worksheet panes' ],
+    [ 'ignore_errors.c',        'Example of ignoring worksheet errors/warnings' ],
     [ 'chart.c',                'Example of a simple column chart' ],
     [ 'chart_area.c',           'Examples of area charts' ],
     [ 'chart_bar.c',            'Examples of bar charts' ],

docs/src/examples.dox

@@ -581,7 +581,7 @@ Example of hiding rows and columns in an Excel worksheet.
 <table  width="600">
 <tr>
   <td>@ref hide_row_col.c "&lt;&lt; hide_row_col.c"</td>
-  <td align="right">@ref chart.c "chart.c &gt;&gt;"</td>
+  <td align="right">@ref ignore_errors.c "ignore_errors.c &gt;&gt;"</td>
 </tr>
 </table>
 
@@ -593,11 +593,27 @@ An example of how to create panes in a worksheet, both "freeze" panes and
 
 
 
-@example chart.c
+@example ignore_errors.c
 
 <table  width="600">
 <tr>
   <td>@ref panes.c "&lt;&lt; panes.c"</td>
+  <td align="right">@ref chart.c "chart.c &gt;&gt;"</td>
+</tr>
+</table>
+
+Example of hiding worksheet errors and warnings.
+
+@image html ignore_errors2.png
+
+
+
+
+@example chart.c
+
+<table  width="600">
+<tr>
+  <td>@ref ignore_errors.c "&lt;&lt; ignore_errors.c"</td>
   <td align="right">@ref chart_area.c "chart_area.c &gt;&gt;"</td>
 </tr>
 </table>

docs/src/examples.txt

@@ -266,6 +266,13 @@ An example of how to create panes in a worksheet, both "freeze" panes and
 
 @image html panes.png
 
+##############################################################
+@example ignore_errors.c
+
+Example of hiding worksheet errors and warnings.
+
+@image html ignore_errors2.png
+
 ##############################################################
 @example chart.c
 

examples/ignore_errors.c

@@ -0,0 +1,38 @@
+/*
+ * An example of turning off worksheet cells errors/warnings using
+ * libxlsxwriter.
+ *
+ * Copyright 2014-2020, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = workbook_new("ignore_errors.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+
+    /* Write strings that looks like numbers. This will cause an Excel warning. */
+    worksheet_write_string(worksheet, CELL("C2"), "123", NULL);
+    worksheet_write_string(worksheet, CELL("C3"), "123", NULL);
+
+    /* Write a divide by zero formula. This will also cause an Excel warning. */
+    worksheet_write_formula(worksheet, CELL("C5"), "=1/0", NULL);
+    worksheet_write_formula(worksheet, CELL("C6"), "=1/0", NULL);
+
+    /* Turn off some of the warnings: */
+    worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "C3");
+    worksheet_ignore_errors(worksheet, LXW_IGNORE_EVAL_ERROR,            "C6");
+
+    /* Write some descriptions for the cells and make the column wider for clarity. */
+    worksheet_set_column(worksheet, 1, 1, 16, NULL);
+    worksheet_write_string(worksheet, CELL("B2"), "Warning:",            NULL);
+    worksheet_write_string(worksheet, CELL("B3"), "Warning turned off:", NULL);
+    worksheet_write_string(worksheet, CELL("B5"), "Warning:",            NULL);
+    worksheet_write_string(worksheet, CELL("B6"), "Warning turned off:", NULL);
+
+    workbook_close(workbook);
+
+    return 0;
+}

include/xlsxwriter/worksheet.h

@@ -239,6 +239,44 @@ enum lxw_object_position {
     LXW_OBJECT_MOVE_AND_SIZE_AFTER
 };
 
+/** Options for ignoring worksheet errors/warnings. See worksheet_ignore_errors(). */
+enum lxw_ignore_errors {
+
+    /** Turn off errors/warnings for numbers stores as text. */
+    LXW_IGNORE_NUMBER_STORED_AS_TEXT = 1,
+
+    /** Turn off errors/warnings for formula errors (such as divide by
+     *  zero). */
+    LXW_IGNORE_EVAL_ERROR,
+
+    /** Turn off errors/warnings for formulas that differ from surrounding
+     *  formulas. */
+    LXW_IGNORE_FORMULA_DIFFERS,
+
+    /** Turn off errors/warnings for formulas that omit cells in a range. */
+    LXW_IGNORE_FORMULA_RANGE,
+
+    /** Turn off errors/warnings for unlocked cells that contain formulas. */
+    LXW_IGNORE_FORMULA_UNLOCKED,
+
+    /** Turn off errors/warnings for formulas that refer to empty cells. */
+    LXW_IGNORE_EMPTY_CELL_REFERENCE,
+
+    /** Turn off errors/warnings for cells in a table that do not comply with
+     *  applicable data validation rules. */
+    LXW_IGNORE_LIST_DATA_VALIDATION,
+
+    /** Turn off errors/warnings for cell formulas that differ from the column
+     *  formula. */
+    LXW_IGNORE_CALCULATED_COLUMN,
+
+    /** Turn off errors/warnings for formulas that contain a two digit text
+     *  representation of a year. */
+    LXW_IGNORE_TWO_DIGIT_TEXT_YEAR,
+
+    LXW_IGNORE_LAST_OPTION
+};
+
 enum cell_types {
     NUMBER_CELL = 1,
     STRING_CELL,
@@ -1062,6 +1100,17 @@ typedef struct lxw_worksheet {
     uint32_t vml_shape_id;
     uint8_t comment_display_default;
 
+    uint8_t has_ignore_errors;
+    char *ignore_number_stored_as_text;
+    char *ignore_eval_error;
+    char *ignore_formula_differs;
+    char *ignore_formula_range;
+    char *ignore_formula_unlocked;
+    char *ignore_empty_cell_reference;
+    char *ignore_list_data_validation;
+    char *ignore_calculated_column;
+    char *ignore_two_digit_text_year;
+
     STAILQ_ENTRY (lxw_worksheet) list_pointers;
 
 } lxw_worksheet;
@@ -3687,6 +3736,8 @@ void worksheet_set_default_row(lxw_worksheet *worksheet, double height,
  * @param worksheet Pointer to a lxw_worksheet instance.
  * @param name      Name of the worksheet used by VBA.
  *
+ * @return A #lxw_error.
+ *
  * The `worksheet_set_vba_name()` function can be used to set the VBA name for
  * the worksheet. This is sometimes required when a vbaProject macro included
  * via `workbook_add_vba_project()` refers to the worksheet by a name other
@@ -3702,8 +3753,6 @@ void worksheet_set_default_row(lxw_worksheet *worksheet, double height,
  * extracted from a foreign language version of Excel.
  *
  * See also @ref working_with_macros
- *
- * @return A #lxw_error.
  */
 lxw_error worksheet_set_vba_name(lxw_worksheet *worksheet, const char *name);
 
@@ -3745,6 +3794,107 @@ void worksheet_show_comments(lxw_worksheet *worksheet);
 void worksheet_set_comments_author(lxw_worksheet *worksheet,
                                    const char *author);
 
+/**
+ * @brief Ignore various Excel errors/warnings in a worksheet for user
+ *        defined ranges.
+ *
+ * @param worksheet Pointer to a lxw_worksheet instance.
+ * @param type      The type of error/warning to ignore. See #lxw_ignore_errors.
+ * @param range     The range(s) for which the error/warning should be ignored.
+ *
+ * @return A #lxw_error.
+ *
+ *
+ * The `%worksheet_ignore_errors()` function can be used to ignore various
+ * worksheet cell errors/warnings. For example the following code writes a string
+ * that looks like a number:
+ *
+ * @code
+ *     worksheet_write_string(worksheet, CELL("D2"), "123", NULL);
+ * @endcode
+ *
+ * This causes Excel to display a small green triangle in the top left hand
+ * corner of the cell to indicate an error/warning:
+ *
+ * @image html ignore_errors1.png
+ *
+ * Sometimes these warnings are useful indicators that there is an issue in
+ * the spreadsheet but sometimes it is preferable to turn them off. Warnings
+ * can be turned off at the Excel level for all workbooks and worksheets by
+ * using the using "Excel options -> Formulas -> Error checking
+ * rules". Alternatively you can turn them off for individual cells in a
+ * worksheet, or ranges of cells, using the `%worksheet_ignore_errors()`
+ * function with different #lxw_ignore_errors options and ranges like this:
+ *
+ * @code
+ *     worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "C3");
+ *     worksheet_ignore_errors(worksheet, LXW_IGNORE_EVAL_ERROR,            "C6");
+ * @endcode
+ *
+ * The range can be a single cell, a range of cells, or multiple cells and ranges
+ * separated by spaces:
+ *
+ * @code
+ *     // Single cell.
+ *     worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "C6");
+ *
+ *     // Or a single range:
+ *     worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "C6:G8");
+ *
+ *     // Or multiple cells and ranges:
+ *     worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "C6 E6 G1:G20 J2:J6");
+ * @endcode
+ *
+ * @note Calling `%worksheet_ignore_errors()` more than once for the same
+ * #lxw_ignore_errors type will overwrite the previous range.
+ *
+ * You can turn off warnings for an entire column by specifying the range from
+ * the first cell in the column to the last cell in the column:
+ *
+ * @code
+ *     worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "A1:A1048576");
+ * @endcode
+ *
+ * Or for the entire worksheet by specifying the range from the first cell in
+ * the worksheet to the last cell in the worksheet:
+ *
+ * @code
+ *     worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "A1:XFD1048576");
+ * @endcode
+ *
+ * The worksheet errors/warnings that can be ignored are:
+ *
+ * - #LXW_IGNORE_NUMBER_STORED_AS_TEXT: Turn off errors/warnings for numbers
+ *    stores as text.
+ *
+ * - #LXW_IGNORE_EVAL_ERROR: Turn off errors/warnings for formula errors (such
+ *    as divide by zero).
+ *
+ * - #LXW_IGNORE_FORMULA_DIFFERS: Turn off errors/warnings for formulas that
+ *    differ from surrounding formulas.
+ *
+ * - #LXW_IGNORE_FORMULA_RANGE: Turn off errors/warnings for formulas that
+ *    omit cells in a range.
+ *
+ * - #LXW_IGNORE_FORMULA_UNLOCKED: Turn off errors/warnings for unlocked cells
+ *    that contain formulas.
+ *
+ * - #LXW_IGNORE_EMPTY_CELL_REFERENCE: Turn off errors/warnings for formulas
+ *    that refer to empty cells.
+ *
+ * - #LXW_IGNORE_LIST_DATA_VALIDATION: Turn off errors/warnings for cells in a
+ *    table that do not comply with applicable data validation rules.
+ *
+ * - #LXW_IGNORE_CALCULATED_COLUMN: Turn off errors/warnings for cell formulas
+ *    that differ from the column formula.
+ *
+ * - #LXW_IGNORE_TWO_DIGIT_TEXT_YEAR: Turn off errors/warnings for formulas
+ *    that contain a two digit text representation of a year.
+ *
+ */
+lxw_error worksheet_ignore_errors(lxw_worksheet *worksheet, uint8_t type,
+                                  const char *range);
+
 lxw_worksheet *lxw_worksheet_new(lxw_worksheet_init_data *init_data);
 void lxw_worksheet_free(lxw_worksheet *worksheet);
 void lxw_worksheet_assemble_xml_file(lxw_worksheet *worksheet);
@@ -3768,7 +3918,7 @@ uint32_t lxw_worksheet_prepare_vml_objects(lxw_worksheet *worksheet,
 lxw_row *lxw_worksheet_find_row(lxw_worksheet *worksheet, lxw_row_t row_num);
 lxw_cell *lxw_worksheet_find_cell_in_row(lxw_row *row, lxw_col_t col_num);
 /*
- * External functions to call intern XML methods shared with chartsheet.
+ * External functions to call intern XML functions shared with chartsheet.
  */
 void lxw_worksheet_write_sheet_views(lxw_worksheet *worksheet);
 void lxw_worksheet_write_page_margins(lxw_worksheet *worksheet);

src/Makefile

@@ -66,7 +66,7 @@ CFLAGS += -DUSE_FMEMOPEN
 endif
 
 # Flags passed to compiler.
-CFLAGS   += -g -O3 -Wall -Wextra -Wstrict-prototypes -pedantic -ansi
+CFLAGS   += -g -O0 -Wall -Wextra -Wstrict-prototypes -pedantic -ansi
 
 # Fix for modified zconf.h on Gentoo.
 ifneq (,$(findstring gentoo, $(shell uname -sr)))

src/worksheet.c

@@ -537,6 +537,15 @@ lxw_worksheet_free(lxw_worksheet *worksheet)
     free(worksheet->vba_codename);
     free(worksheet->vml_data_id_str);
     free(worksheet->comment_author);
+    free(worksheet->ignore_number_stored_as_text);
+    free(worksheet->ignore_eval_error);
+    free(worksheet->ignore_formula_differs);
+    free(worksheet->ignore_formula_range);
+    free(worksheet->ignore_formula_unlocked);
+    free(worksheet->ignore_empty_cell_reference);
+    free(worksheet->ignore_list_data_validation);
+    free(worksheet->ignore_calculated_column);
+    free(worksheet->ignore_two_digit_text_year);
 
     free(worksheet);
     worksheet = NULL;
@@ -4377,6 +4386,84 @@ _worksheet_write_data_validations(lxw_worksheet *self)
     LXW_FREE_ATTRIBUTES();
 }
 
+/*
+ * Write the <ignoredError> element.
+ */
+STATIC void
+_worksheet_write_ignored_error(lxw_worksheet *self, char *ignore_error,
+                               char *range)
+{
+    struct xml_attribute_list attributes;
+    struct xml_attribute *attribute;
+
+    LXW_INIT_ATTRIBUTES();
+    LXW_PUSH_ATTRIBUTES_STR("sqref", range);
+    LXW_PUSH_ATTRIBUTES_STR(ignore_error, "1");
+
+    lxw_xml_empty_tag(self->file, "ignoredError", &attributes);
+
+    LXW_FREE_ATTRIBUTES();
+}
+
+/*
+ * Write the <ignoredErrors> element.
+ */
+STATIC void
+_worksheet_write_ignored_errors(lxw_worksheet *self)
+{
+    if (!self->has_ignore_errors)
+        return;
+
+    lxw_xml_start_tag(self->file, "ignoredErrors", NULL);
+
+    if (self->ignore_number_stored_as_text) {
+        _worksheet_write_ignored_error(self, "numberStoredAsText",
+                                       self->ignore_number_stored_as_text);
+    }
+
+    if (self->ignore_eval_error) {
+        _worksheet_write_ignored_error(self, "evalError",
+                                       self->ignore_eval_error);
+    }
+
+    if (self->ignore_formula_differs) {
+        _worksheet_write_ignored_error(self, "formula",
+                                       self->ignore_formula_differs);
+    }
+
+    if (self->ignore_formula_range) {
+        _worksheet_write_ignored_error(self, "formulaRange",
+                                       self->ignore_formula_range);
+    }
+
+    if (self->ignore_formula_unlocked) {
+        _worksheet_write_ignored_error(self, "unlockedFormula",
+                                       self->ignore_formula_unlocked);
+    }
+
+    if (self->ignore_empty_cell_reference) {
+        _worksheet_write_ignored_error(self, "emptyCellReference",
+                                       self->ignore_empty_cell_reference);
+    }
+
+    if (self->ignore_list_data_validation) {
+        _worksheet_write_ignored_error(self, "listDataValidation",
+                                       self->ignore_list_data_validation);
+    }
+
+    if (self->ignore_calculated_column) {
+        _worksheet_write_ignored_error(self, "calculatedColumn",
+                                       self->ignore_calculated_column);
+    }
+
+    if (self->ignore_two_digit_text_year) {
+        _worksheet_write_ignored_error(self, "twoDigitTextYear",
+                                       self->ignore_two_digit_text_year);
+    }
+
+    lxw_xml_end_tag(self->file, "ignoredErrors");
+}
+
 /*
  * External functions to call intern XML methods shared with chartsheet.
  */
@@ -4489,6 +4576,9 @@ lxw_worksheet_assemble_xml_file(lxw_worksheet *self)
     /* Write the colBreaks element. */
     _worksheet_write_col_breaks(self);
 
+    /* Write the ignoredErrors element. */
+    _worksheet_write_ignored_errors(self);
+
     /* Write the drawing element. */
     _worksheet_write_drawings(self);
 
@@ -6851,3 +6941,62 @@ worksheet_show_comments(lxw_worksheet *self)
 {
     self->comment_display_default = LXW_COMMENT_DISPLAY_VISIBLE;
 }
+
+/*
+ * Ignore various Excel errors/warnings in a worksheet for user defined ranges.
+ */
+lxw_error
+worksheet_ignore_errors(lxw_worksheet *self, uint8_t type, const char *range)
+{
+    if (!range) {
+        LXW_WARN("worksheet_ignore_errors(): " "'range' must be specified.");
+        return LXW_ERROR_NULL_PARAMETER_IGNORED;
+    }
+
+    if (type <= 0 || type >= LXW_IGNORE_LAST_OPTION) {
+        LXW_WARN("worksheet_ignore_errors(): " "unknown option in 'type'.");
+        return LXW_ERROR_NULL_PARAMETER_IGNORED;
+    }
+
+    /* Set the ranges to be ignored. */
+    if (type == LXW_IGNORE_NUMBER_STORED_AS_TEXT) {
+        free(self->ignore_number_stored_as_text);
+        self->ignore_number_stored_as_text = lxw_strdup(range);
+    }
+    else if (type == LXW_IGNORE_EVAL_ERROR) {
+        free(self->ignore_eval_error);
+        self->ignore_eval_error = lxw_strdup(range);
+    }
+    else if (type == LXW_IGNORE_FORMULA_DIFFERS) {
+        free(self->ignore_formula_differs);
+        self->ignore_formula_differs = lxw_strdup(range);
+    }
+    else if (type == LXW_IGNORE_FORMULA_RANGE) {
+        free(self->ignore_formula_range);
+        self->ignore_formula_range = lxw_strdup(range);
+    }
+    else if (type == LXW_IGNORE_FORMULA_UNLOCKED) {
+        free(self->ignore_formula_unlocked);
+        self->ignore_formula_unlocked = lxw_strdup(range);
+    }
+    else if (type == LXW_IGNORE_EMPTY_CELL_REFERENCE) {
+        free(self->ignore_empty_cell_reference);
+        self->ignore_empty_cell_reference = lxw_strdup(range);
+    }
+    else if (type == LXW_IGNORE_LIST_DATA_VALIDATION) {
+        free(self->ignore_list_data_validation);
+        self->ignore_list_data_validation = lxw_strdup(range);
+    }
+    else if (type == LXW_IGNORE_CALCULATED_COLUMN) {
+        free(self->ignore_calculated_column);
+        self->ignore_calculated_column = lxw_strdup(range);
+    }
+    else if (type == LXW_IGNORE_TWO_DIGIT_TEXT_YEAR) {
+        free(self->ignore_two_digit_text_year);
+        self->ignore_two_digit_text_year = lxw_strdup(range);
+    }
+
+    self->has_ignore_errors = LXW_TRUE;
+
+    return LXW_NO_ERROR;
+}

test/functional/src/test_ignore_error01.c

@@ -0,0 +1,20 @@
+/*****************************************************************************
+ * Test cases for libxlsxwriter.
+ *
+ * Test to compare output against Excel files.
+ *
+ * Copyright 2014-2020, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = workbook_new("test_ignore_error01.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+
+    worksheet_write_string(worksheet, CELL("A1"), "123" , NULL);
+
+    return workbook_close(workbook);
+}

test/functional/src/test_ignore_error02.c

@@ -0,0 +1,22 @@
+/*****************************************************************************
+ * Test cases for libxlsxwriter.
+ *
+ * Test to compare output against Excel files.
+ *
+ * Copyright 2014-2020, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = workbook_new("test_ignore_error02.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+
+    worksheet_write_string(worksheet, CELL("A1"), "123" , NULL);
+
+    worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "A1");
+
+    return workbook_close(workbook);
+}

test/functional/src/test_ignore_error03.c

@@ -0,0 +1,24 @@
+/*****************************************************************************
+ * Test cases for libxlsxwriter.
+ *
+ * Test to compare output against Excel files.
+ *
+ * Copyright 2014-2020, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = workbook_new("test_ignore_error03.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+
+    int row;
+    for (row = 0; row < 10; row++)
+        worksheet_write_string(worksheet, row, 0, "123" , NULL);
+
+    worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "A1:A10");
+
+    return workbook_close(workbook);
+}

test/functional/src/test_ignore_error04.c

@@ -0,0 +1,24 @@
+/*****************************************************************************
+ * Test cases for libxlsxwriter.
+ *
+ * Test to compare output against Excel files.
+ *
+ * Copyright 2014-2020, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = workbook_new("test_ignore_error04.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+
+    worksheet_write_string(worksheet, CELL("A1"), "123" , NULL);
+    worksheet_write_string(worksheet, CELL("C3"), "123" , NULL);
+    worksheet_write_string(worksheet, CELL("E5"), "123" , NULL);
+
+    worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "A1 C3 E5");
+
+    return workbook_close(workbook);
+}

test/functional/src/test_ignore_error05.c

@@ -0,0 +1,27 @@
+/*****************************************************************************
+ * Test cases for libxlsxwriter.
+ *
+ * Test to compare output against Excel files.
+ *
+ * Copyright 2014-2020, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = workbook_new("test_ignore_error05.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+
+    worksheet_write_string(worksheet, CELL("A1"), "123" , NULL);
+    worksheet_write_formula(worksheet, CELL("A2"), "=1/0", NULL);
+
+    worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "A1");
+    /* Duplicate command to test for leaks. */
+    worksheet_ignore_errors(worksheet, LXW_IGNORE_NUMBER_STORED_AS_TEXT, "A1");
+
+    worksheet_ignore_errors(worksheet, LXW_IGNORE_EVAL_ERROR, "A2");
+
+    return workbook_close(workbook);
+}

test/functional/src/test_ignore_error06.c

@@ -0,0 +1,24 @@
+/*****************************************************************************
+ * Test cases for libxlsxwriter.
+ *
+ * Test to compare output against Excel files.
+ *
+ * Copyright 2014-2020, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = workbook_new("test_ignore_error06.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+
+    worksheet_write_formula(worksheet, CELL("A1"), "=B1" , NULL);
+    worksheet_write_formula(worksheet, CELL("A2"), "=B1" , NULL);
+    worksheet_write_formula(worksheet, CELL("A3"), "=B3" , NULL);
+
+    worksheet_ignore_errors(worksheet, LXW_IGNORE_FORMULA_DIFFERS, "A2");
+
+    return workbook_close(workbook);
+}

test/functional/test_ignore_errors.py

@@ -0,0 +1,41 @@
+###############################################################################
+#
+# Tests for libxlsxwriter.
+#
+# Copyright 2014-2020, John McNamara, jmcnamara@cpan.org
+#
+
+import base_test_class
+
+class TestCompareXLSXFiles(base_test_class.XLSXBaseTest):
+    """
+    Test file created with libxlsxwriter against a file created by Excel.
+
+    """
+
+    def test_ignore_error01(self):
+        self.run_exe_test('test_ignore_error01')
+
+    def test_ignore_error02(self):
+        self.run_exe_test('test_ignore_error02')
+
+    def test_ignore_error03(self):
+        self.run_exe_test('test_ignore_error03')
+
+    def test_ignore_error04(self):
+        self.run_exe_test('test_ignore_error04')
+
+    def test_ignore_error05(self):
+        self.ignore_files = ['xl/calcChain.xml',
+                             '[Content_Types].xml',
+                             'xl/_rels/workbook.xml.rels']
+        self.ignore_elements = {'xl/worksheets/sheet1.xml': ['<c', '<v']}
+
+        self.run_exe_test('test_ignore_error05')
+
+    def test_ignore_error06(self):
+        self.ignore_files = ['xl/calcChain.xml',
+                             '[Content_Types].xml',
+                             'xl/_rels/workbook.xml.rels']
+
+        self.run_exe_test('test_ignore_error06')