projects / thirdparty / man-pages.git / blame
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| bf5a7247 | 1 | .\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de) |
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2 | .\" |
| 3 | .\" Permission is granted to make and distribute verbatim copies of this | |
| 4 | .\" manual provided the copyright notice and this permission notice are | |
| 5 | .\" preserved on all copies. | |
| 6 | .\" | |
| 7 | .\" Permission is granted to copy and distribute modified versions of this | |
| 8 | .\" manual under the conditions for verbatim copying, provided that the | |
| 9 | .\" entire resulting derived work is distributed under the terms of a | |
| 10 | .\" permission notice identical to this one. | |
| c13182ef | 11 | .\" |
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12 | .\" Since the Linux kernel and libraries are constantly changing, this |
| 13 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
| 14 | .\" responsibility for errors or omissions, or for damages resulting from | |
| 15 | .\" the use of the information contained herein. The author(s) may not | |
| 16 | .\" have taken the same level of care in the production of this manual, | |
| 17 | .\" which is licensed free of charge, as they might when working | |
| 18 | .\" professionally. | |
| c13182ef | 19 | .\" |
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20 | .\" Formatted or processed versions of this manual, if unaccompanied by |
| 21 | .\" the source, must acknowledge the copyright and authors of this work. | |
| 22 | .\" License. | |
| 23 | .\" Modified Sat Jul 24 21:42:42 1993 by Rik Faith <faith@cs.unc.edu> | |
| 24 | .\" Modified Tue Oct 22 23:44:11 1996 by Eric S. Raymond <esr@thyrsus.com> | |
| 69962544 | 25 | .TH ASSERT 3 2002-08-25 "GNU" "Linux Programmer's Manual" |
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26 | .SH NAME |
| 27 | assert \- abort the program if assertion is false | |
| 28 | .SH SYNOPSIS | |
| 29 | .nf | |
| 30 | .B #include <assert.h> | |
| 31 | .sp | |
| 32 | .BI "void assert(scalar " expression ); | |
| 33 | .fi | |
| 34 | .SH DESCRIPTION | |
| 35 | If the macro | |
| 36 | .B NDEBUG | |
| 37 | was defined at the moment | |
| bd12ab88 | 38 | .I <assert.h> |
| fea681da | 39 | was last included, the macro |
| 63aa9df0 | 40 | .BR assert () |
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41 | generates no code, and hence does nothing at all. |
| 42 | Otherwise, the macro | |
| 63aa9df0 | 43 | .BR assert () |
| 4c39c55c | 44 | prints an error message to standard error and terminates the program |
| fea681da | 45 | by calling |
| fb186734 | 46 | .BR abort (3) |
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47 | if |
| 48 | .I expression | |
| 49 | is false (i.e., compares equal to zero). | |
| 50 | .LP | |
| 51 | The purpose of this macro is to help the programmer find bugs in | |
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52 | his program. |
| 53 | The message "assertion failed in file foo.c, function | |
| fea681da | 54 | do_bar(), line 1287" is of no help at all to a user. |
| 47297adb | 55 | .SH RETURN VALUE |
| fea681da | 56 | No value is returned. |
| 47297adb | 57 | .SH CONFORMING TO |
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58 | POSIX.1-2001, C89, C99. |
| 59 | In C89, | |
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60 | .I expression |
| 61 | is required to be of type | |
| 9ff08aad | 62 | .I int |
| 68e1685c | 63 | and undefined behavior results if it is not, but in C99 |
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64 | it may have any scalar type. |
| 65 | .\" See Defect Report 107 for more details. | |
| 66 | .SH BUGS | |
| 63aa9df0 | 67 | .BR assert () |
| fea681da | 68 | is implemented as a macro; if the expression tested has side-effects, |
| d9bfdb9c | 69 | program behavior will be different depending on whether |
| fea681da | 70 | .B NDEBUG |
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71 | is defined. |
| 72 | This may create Heisenbugs which go away when debugging | |
| fea681da | 73 | is turned on. |
| 47297adb | 74 | .SH SEE ALSO |
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75 | .BR abort (3), |
| 76 | .BR assert_perror (3), | |
| 77 | .BR exit (3) |