strlen(3)

1strlen(3)                  Library Functions Manual                  strlen(3)
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NAME

6       strlen - calculate the length of a string
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LIBRARY

9       Standard C library (libc, -lc)
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SYNOPSIS

12       #include <string.h>
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14       size_t strlen(const char *s);
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DESCRIPTION

17       The strlen() function calculates the length of the string pointed to by
18       s, excluding the terminating null byte ('\0').
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RETURN VALUE

21       The strlen() function returns the number of bytes in the string pointed
22       to by s.
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ATTRIBUTES

25       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
26       tributes(7).
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28       ┌────────────────────────────────────────────┬───────────────┬─────────┐
29       │Interface                                   │ Attribute     │ Value   │
30       ├────────────────────────────────────────────┼───────────────┼─────────┤
31       │strlen()                                    │ Thread safety │ MT-Safe │
32       └────────────────────────────────────────────┴───────────────┴─────────┘
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STANDARDS

35       C11, POSIX.1-2008.
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HISTORY

38       POSIX.1-2001, C89, SVr4, 4.3BSD.
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NOTES

41       In cases where the input buffer may  not  contain  a  terminating  null
42       byte, strnlen(3) should be used instead.
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