This handy C library can read and write time format strings in four formats: Excel (TFS_EXCEL), POSIX (TFS_POSIX), Stata (TFS_STATA), and Unicode (TFS_UTS35).

It can also read, but not write, format strings in SAS format (TFS_SAS) and SPSS format (TFS_SPSS).

Example usage:

#include "tfs.h"

char result[100];
tfs_error_e error = tfs_convert("mm/dd/yyyy", TFS_EXCEL,
                                result, TFS_UTS35, sizeof(result));
if (error == TFS_OK) {
    printf("%s\n", result); /* prints "MM/dd/y" */
}

The POSIX format can be fed to strftime and strptime in order to present and parse specific time values.

Type "make" to build the library and "make test" to run the test suite.