CURLOPT_POSTFIELDS.3 3.9 KB

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  25. .TH CURLOPT_POSTFIELDS 3 "May 17, 2022" "libcurl 7.85.0" "curl_easy_setopt options"
  26. .SH NAME
  27. CURLOPT_POSTFIELDS \- data to POST to server
  28. .SH SYNOPSIS
  29. .nf
  30. #include <curl/curl.h>
  31. CURLcode curl_easy_setopt(CURL *handle, CURLOPT_POSTFIELDS, char *postdata);
  32. .fi
  33. .SH DESCRIPTION
  34. Pass a char * as parameter, pointing to the full data to send in an HTTP POST
  35. operation. You must make sure that the data is formatted the way you want the
  36. server to receive it. libcurl will not convert or encode it for you in any
  37. way. For example, the web server may assume that this data is url-encoded.
  38. The data pointed to is NOT copied by the library: as a consequence, it must be
  39. preserved by the calling application until the associated transfer finishes.
  40. This behavior can be changed (so libcurl does copy the data) by setting the
  41. \fICURLOPT_COPYPOSTFIELDS(3)\fP option.
  42. This POST is a normal application/x-www-form-urlencoded kind (and libcurl will
  43. set that Content-Type by default when this option is used), which is commonly
  44. used by HTML forms. Change Content-Type with \fICURLOPT_HTTPHEADER(3)\fP.
  45. You can use \fIcurl_easy_escape(3)\fP to url-encode your data, if necessary. It
  46. returns a pointer to an encoded string that can be passed as \fIpostdata\fP.
  47. Using \fICURLOPT_POSTFIELDS(3)\fP implies setting \fICURLOPT_POST(3)\fP to 1.
  48. If \fICURLOPT_POSTFIELDS(3)\fP is explicitly set to NULL then libcurl will get
  49. the POST data from the read callback. If you want to send a zero-byte POST set
  50. \fICURLOPT_POSTFIELDS(3)\fP to an empty string, or set \fICURLOPT_POST(3)\fP to
  51. 1 and \fICURLOPT_POSTFIELDSIZE(3)\fP to 0.
  52. libcurl will use assume this option points to a nul-terminated string unless
  53. you also set \fICURLOPT_POSTFIELDSIZE(3)\fP to specify the length of the
  54. provided data, which then is strictly required if you want to send off nul
  55. bytes included in the data.
  56. Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header,
  57. and libcurl will add that header automatically if the POST is either known to
  58. be larger than 1MB or if the expected size is unknown. You can disable this
  59. header with \fICURLOPT_HTTPHEADER(3)\fP as usual.
  60. To make multipart/formdata posts (aka RFC2388-posts), check out the
  61. \fICURLOPT_HTTPPOST(3)\fP option combined with \fIcurl_formadd(3)\fP.
  62. .SH DEFAULT
  63. NULL
  64. .SH PROTOCOLS
  65. HTTP
  66. .SH EXAMPLE
  67. .nf
  68. CURL *curl = curl_easy_init();
  69. if(curl) {
  70. const char *data = "data to send";
  71. curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
  72. /* size of the POST data */
  73. curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, 12L);
  74. /* pass in a pointer to the data - libcurl will not copy */
  75. curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data);
  76. curl_easy_perform(curl);
  77. }
  78. .fi
  79. .SH AVAILABILITY
  80. Always
  81. .SH RETURN VALUE
  82. Returns CURLE_OK
  83. .SH "SEE ALSO"
  84. .BR CURLOPT_POSTFIELDSIZE "(3), " CURLOPT_READFUNCTION "(3), "