1STRNCMP(3P) POSIX Programmer's Manual STRNCMP(3P)
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6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
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12 strncmp — compare part of two strings
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15 #include <string.h>
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17 int strncmp(const char *s1, const char *s2, size_t n);
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20 The functionality described on this reference page is aligned with the
21 ISO C standard. Any conflict between the requirements described here
22 and the ISO C standard is unintentional. This volume of POSIX.1‐2017
23 defers to the ISO C standard.
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25 The strncmp() function shall compare not more than n bytes (bytes that
26 follow a NUL character are not compared) from the array pointed to by
27 s1 to the array pointed to by s2.
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29 The sign of a non-zero return value is determined by the sign of the
30 difference between the values of the first pair of bytes (both inter‐
31 preted as type unsigned char) that differ in the strings being com‐
32 pared.
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35 Upon successful completion, strncmp() shall return an integer greater
36 than, equal to, or less than 0, if the possibly null-terminated array
37 pointed to by s1 is greater than, equal to, or less than the possibly
38 null-terminated array pointed to by s2 respectively.
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41 No errors are defined.
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43 The following sections are informative.
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46 None.
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49 None.
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52 None.
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55 None.
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58 strcmp()
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60 The Base Definitions volume of POSIX.1‐2017, <string.h>
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63 Portions of this text are reprinted and reproduced in electronic form
64 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
65 table Operating System Interface (POSIX), The Open Group Base Specifi‐
66 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
67 Electrical and Electronics Engineers, Inc and The Open Group. In the
68 event of any discrepancy between this version and the original IEEE and
69 The Open Group Standard, the original IEEE and The Open Group Standard
70 is the referee document. The original Standard can be obtained online
71 at http://www.opengroup.org/unix/online.html .
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73 Any typographical or formatting errors that appear in this page are
74 most likely to have been introduced during the conversion of the source
75 files to man page format. To report such errors, see https://www.ker‐
76 nel.org/doc/man-pages/reporting_bugs.html .
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80IEEE/The Open Group 2017 STRNCMP(3P)