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utils-std

Collection of commonly available Unix tools git clone https://anongit.hacktivis.me/git/utils-std.git/

nproc.c (1911B)

    

  1. // utils-std: Collection of commonly available Unix tools
  2. // SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
  3. // SPDX-License-Identifier: MPL-2.0
  5. // _SC_NPROCESSORS_CONF &_SC_NPROCESSORS_ONLN got added in POSIX.1-2024
  6. // https://www.austingroupbugs.net/view.php?id=339
  7. #define _DEFAULT_SOURCE
  9. // Sadly {Free,Net}BSD hides _SC_NPROCESSORS_{CONF,ONLN} if _POSIX_C_SOURCE is defined *sigh*
  10. // #define _POSIX_C_SOURCE 202405L
  12. #include "../config.h"
  13. #include "../libutils/getopt_nolong.h"
  15. #include <errno.h>
  16. #include <stdio.h>  // printf
  17. #include <string.h> // strerror
  18. #include <unistd.h> // sysconf, getopt, opt*
  19. #ifdef HAS_GETOPT_LONG
  20. #include <getopt.h>
  21. #endif
  23. const char *argv0 = "nproc";
  25. static void
  26. usage(void)
  27. {
  28. 	fprintf(stderr, "Usage: nproc [-a]\n");
  29. }
  31. int
  32. main(int argc, char *argv[])
  33. {
  34. 	// currently available
  35. 	int target = _SC_NPROCESSORS_ONLN;
  36. 	const char *target_str = "_SC_NPROCESSORS_ONLN";
  38. #ifdef HAS_GETOPT_LONG
  39. 	// Strictly for GNUisms compatibility so no long-only options
  40. 	// clang-format off
  41. 	static struct option opts[] = {
  42. 		{"all", no_argument, NULL, 'a'},
  43. 		{0, 0, 0, 0},
  44. 	};
  45. 	// clang-format on
  47. 	// Need + as first character to get POSIX-style option parsing
  48. 	for(int c = -1; (c = getopt_long(argc, argv, "+:a", opts, NULL)) != -1;)
  49. #else
  50. 	for(int c = -1; (c = getopt_nolong(argc, argv, ":a")) != -1;)
  51. #endif
  52. 	{
  53. 		switch(c)
  54. 		{
  55. 		case 'a': // can be made available
  56. 			target = _SC_NPROCESSORS_CONF;
  57. 			target_str = "_SC_NPROCESSORS_CONF";
  58. 			break;
  59. 		case ':':
  60. 			fprintf(stderr, "%s: error: Missing operand for option: '-%c'\n", argv0, optopt);
  61. 			usage();
  62. 			return 1;
  63. 		case '?':
  64. 			GETOPT_UNKNOWN_OPT
  65. 			usage();
  66. 			return 1;
  67. 		}
  68. 	}
  70. 	long np = sysconf(target);
  71. 	if(np < 0)
  72. 	{
  73. 		fprintf(
  74. 		    stderr, "%s: error: Failed getting sysconf '%s': %s\n", argv0, target_str, strerror(errno));
  75. 		return 1;
  76. 	}
  78. 	printf("%ld\n", np);
  80. 	return 0;
  81. }