CURLOPT_IOCTLFUNCTION - callback for I/O operations
#include <curl/curl.h> typedef enum { CURLIOE_OK, /* I/O operation successful */ CURLIOE_UNKNOWNCMD, /* command was unknown to callback */ CURLIOE_FAILRESTART, /* failed to restart the read */ CURLIOE_LAST /* never use */ } curlioerr; typedef enum { CURLIOCMD_NOP, /* no operation */ CURLIOCMD_RESTARTREAD, /* restart the read stream from start */ CURLIOCMD_LAST /* never use */ } curliocmd; curlioerr ioctl_callback(CURL *handle, int cmd, void *clientp); CURLcode curl_easy_setopt(CURL *handle, CURLOPT_IOCTLFUNCTION, ioctl_callback);
CURLOPT_IOCTLFUNCTION(3) curl_easy_setopt options CURLOPT_IOCTLFUNCTION(3) NAME CURLOPT_IOCTLFUNCTION - callback for I/O operations SYNOPSIS #include <curl/curl.h> typedef enum { CURLIOE_OK, /* I/O operation successful */ CURLIOE_UNKNOWNCMD, /* command was unknown to callback */ CURLIOE_FAILRESTART, /* failed to restart the read */ CURLIOE_LAST /* never use */ } curlioerr; typedef enum { CURLIOCMD_NOP, /* no operation */ CURLIOCMD_RESTARTREAD, /* restart the read stream from start */ CURLIOCMD_LAST /* never use */ } curliocmd; curlioerr ioctl_callback(CURL *handle, int cmd, void *clientp); CURLcode curl_easy_setopt(CURL *handle, CURLOPT_IOCTLFUNCTION, ioctl_callback); DESCRIPTION Pass a pointer to your callback function, which should match the proto- type shown above. This callback function gets called by libcurl when something special I/O-related needs to be done that the library cannot do by itself. For now, rewinding the read data stream is the only action it can request. The rewinding of the read data stream may be necessary when doing an HTTP PUT or POST with a multi-pass authentication method. The callback MUST return CURLIOE_UNKNOWNCMD if the input cmd is not CURLIOCMD_RESTARTREAD. The clientp argument to the callback is set with the CURLOPT_IOCTL- DATA(3) option. This option is deprecated! Do not use it. Use CURLOPT_SEEKFUNCTION(3) instead to provide seeking! If CURLOPT_SEEKFUNCTION(3) is set, this parameter will be ignored when seeking. DEFAULT By default, this parameter is set to NULL. Not used. PROTOCOLS Used with HTTP EXAMPLE static curlioerr ioctl_callback(CURL *handle, int cmd, void *clientp) { struct data *io = (struct data *)clientp; if(cmd == CURLIOCMD_RESTARTREAD) { lseek(fd, 0, SEEK_SET); current_offset = 0; return CURLIOE_OK; } return CURLIOE_UNKNOWNCMD; } { struct data ioctl_data; curl_easy_setopt(curl, CURLOPT_IOCTLFUNCTION, ioctl_callback); curl_easy_setopt(curl, CURLOPT_IOCTLDATA, &ioctl_data); } AVAILABILITY Added in 7.12.3 RETURN VALUE Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. ATTRIBUTES See attributes(7) for descriptions of the following attributes: +---------------+------------------+ |ATTRIBUTE TYPE | ATTRIBUTE VALUE | +---------------+------------------+ |Availability | web/curl | +---------------+------------------+ |Stability | Uncommitted | +---------------+------------------+ SEE ALSO CURLOPT_IOCTLDATA(3), CURLOPT_SEEKFUNCTION(3), NOTES Source code for open source software components in Oracle Solaris can be found at https://www.oracle.com/downloads/opensource/solaris-source- code-downloads.html. This software was built from source available at https://github.com/oracle/solaris-userland. The original community source was downloaded from https://curl.se/down- load/curl-7.83.1.tar.bz2. Further information about this software can be found on the open source community website at http://curl.haxx.se/. libcurl 7.83.1 October 31, 2021 CURLOPT_IOCTLFUNCTION(3)