Manpages - strcasecmp.3p

This manual page is part of the POSIX Programmer’s Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

strcasecmp, strcasecmp_l, strncasecmp, strncasecmp_l — case-insensitive string comparisons

  #include <strings.h>
  int strcasecmp(const char *s1, const char *s2);
  int strcasecmp_l(const char *s1, const char *s2,
      locale_t locale);
  int strncasecmp(const char *s1, const char *s2, size_t n);
  int strncasecmp_l(const char *s1, const char *s2,
      size_t n, locale_t locale);

The strcasecmp/() and /strcasecmp_l/() functions shall compare, while ignoring differences in case, the string pointed to by /s1 to the string pointed to by s2. The /strncasecmp/() and /strncasecmp_l/() functions shall compare, while ignoring differences in case, not more than n bytes from the string pointed to by s1 to the string pointed to by s2.

The /strcasecmp/() and /strncasecmp/() functions use the current locale to determine the case of the characters.

The strcasecmp_l/() and /strncasecmp_l/() functions use the locale represented by /locale to determine the case of the characters.

When the LC_CTYPE category of the locale being used is from the POSIX locale, these functions shall behave as if the strings had been converted to lowercase and then a byte comparison performed. Otherwise, the results are unspecified.

The behavior is undefined if the locale argument to /strcasecmp_l/() or /strncasecmp_l/() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle.

Upon completion, /strcasecmp/() and /strcasecmp_l/() shall return an integer greater than, equal to, or less than 0, if the string pointed to by s1 is, ignoring case, greater than, equal to, or less than the string pointed to by s2, respectively.

Upon successful completion, /strncasecmp/() and /strncasecmp_l/() shall return an integer greater than, equal to, or less than 0, if the possibly null-terminated array pointed to by s1 is, ignoring case, greater than, equal to, or less than the possibly null-terminated array pointed to by s2, respectively.

No errors are defined.

The following sections are informative.

None.

None.

None.

None.

/wcscasecmp ( )/

The Base Definitions volume of POSIX.1‐2017, <strings.h>

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology – Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

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