1STRDUP(3)                  Linux Programmer's Manual                 STRDUP(3)
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NAME

6       strdup, strndup, strdupa, strndupa - duplicate a string
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SYNOPSIS

9       #include <string.h>
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11       char *strdup(const char *s);
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13       char *strndup(const char *s, size_t n);
14       char *strdupa(const char *s);
15       char *strndupa(const char *s, size_t n);
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17   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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19       strdup():
20           _XOPEN_SOURCE >= 500
21               || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L
22               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
23       strndup():
24           Since glibc 2.10:
25               _POSIX_C_SOURCE >= 200809L
26           Before glibc 2.10:
27               _GNU_SOURCE
28       strdupa(), strndupa(): _GNU_SOURCE
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DESCRIPTION

31       The  strdup() function returns a pointer to a new string which is a du‐
32       plicate of the string s.  Memory for the new string  is  obtained  with
33       malloc(3), and can be freed with free(3).
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35       The strndup() function is similar, but copies at most n bytes.  If s is
36       longer than n, only n bytes are copied, and  a  terminating  null  byte
37       ('\0') is added.
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39       strdupa() and strndupa() are similar, but use alloca(3) to allocate the
40       buffer.  They are available only when using the GNU GCC suite, and suf‐
41       fer from the same limitations described in alloca(3).
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RETURN VALUE

44       On  success,  the strdup() function returns a pointer to the duplicated
45       string.  It returns NULL if insufficient memory was available, with er‐
46       rno set to indicate the cause of the error.
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ERRORS

49       ENOMEM Insufficient memory available to allocate duplicate string.
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ATTRIBUTES

52       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
53       tributes(7).
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55       ┌────────────────────────────────┬───────────────┬─────────┐
56       │Interface                       │ Attribute     │ Value   │
57       ├────────────────────────────────┼───────────────┼─────────┤
58       │strdup(), strndup(), strdupa(), │ Thread safety │ MT-Safe │
59       │strndupa()                      │               │         │
60       └────────────────────────────────┴───────────────┴─────────┘
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CONFORMING TO

63       strdup() conforms to SVr4, 4.3BSD, POSIX.1-2001.  strndup() conforms to
64       POSIX.1-2008.  strdupa() and strndupa() are GNU extensions.
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SEE ALSO

67       alloca(3),  calloc(3),  free(3), malloc(3), realloc(3), string(3), wcs‐
68       dup(3)
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COLOPHON

71       This page is part of release 5.10 of the Linux  man-pages  project.   A
72       description  of  the project, information about reporting bugs, and the
73       latest    version    of    this    page,    can     be     found     at
74       https://www.kernel.org/doc/man-pages/.
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78GNU                               2019-03-06                         STRDUP(3)
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