C Specification

To compile a program’s source for all the devices or a specific device(s) in the OpenCL context associated with the program, call the function

cl_int clCompileProgram(
    cl_program program,
    cl_uint num_devices,
    const cl_device_id* device_list,
    const char* options,
    cl_uint num_input_headers,
    const cl_program* input_headers,
    const char** header_include_names,
    void (CL_CALLBACK* pfn_notify)(cl_program program, void* user_data),
    void* user_data);


  • program is the program object that is the compilation target.

  • device_list is a pointer to a list of devices associated with program. If device_list is a NULL value, the compile is performed for all devices associated with program. If device_list is a non-NULL value, the compile is performed for devices specified in this list.

  • num_devices is the number of devices listed in device_list.

  • options is a pointer to a null-terminated string of characters that describes the compilation options to be used for building the program executable. If options is a NULL pointer then it will have the same result as the empty string. Certain options are ignored when program is created with IL. The list of supported options is as described in Compiler Options.

  • num_input_headers specifies the number of programs that describe headers in the array referenced by input_headers.

  • input_headers is an array of program embedded headers created with clCreateProgramWithSource.

  • header_include_names is an array that has a one to one correspondence with input_headers. Each entry in header_include_names specifies the include name used by source in program that comes from an embedded header. The corresponding entry in input_headers identifies the program object which contains the header source to be used. The embedded headers are first searched before the headers in the list of directories specified by the -I compile option (as described in Preprocessor options). If multiple entries in header_include_names refer to the same header name, the first one encountered will be used.

  • pfn_notify is a function pointer to a notification routine. The notification routine is a callback function that an application can register and which will be called when the program executable has been built (successfully or unsuccessfully). If pfn_notify is not NULL, clCompileProgram does not need to wait for the compiler to complete and can return immediately once the compilation can begin. The compilation can begin if the context, program whose sources are being compiled, list of devices, input headers, programs that describe input headers and compiler options specified are all valid and appropriate host and device resources needed to perform the compile are available. If pfn_notify is NULL, clCompileProgram does not return until the compiler has completed. This callback function may be called asynchronously by the OpenCL implementation. It is the applications responsibility to ensure that the callback function is thread-safe.

    • user_data will be passed as an argument when pfn_notify is called. user_data can be NULL.


The pre-processor runs before the program sources are compiled. The compiled binary is built for all devices associated with program or the list of devices specified. The compiled binary can be queried using clGetProgramInfo(program, CL_​PROGRAM_​BINARIES, …​) and can be passed to clCreateProgramWithBinary to create a new program object.

If program was created using clCreateProgramWithIL, then num_input_headers, input_headers, and header_include_names are ignored.

For example, consider the following program source:

#include <foo.h>
#include <mydir/myinc.h>
__kernel void
image_filter (int n, int m,
              __constant float *filter_weights,
              __read_only image2d_t src_image,
              __write_only image2d_t dst_image)

This kernel includes two headers foo.h and mydir/myinc.h. The following describes how these headers can be passed as embedded headers in program objects:

cl_program foo_pg = clCreateProgramWithSource(context,
    1, &foo_header_src, NULL, &err);
cl_program myinc_pg = clCreateProgramWithSource(context,
    1, &myinc_header_src, NULL, &err);

// lets assume the program source described above is given
// by program_A and is loaded via clCreateProgramWithSource
cl_program input_headers[2] = { foo_pg, myinc_pg };
char * input_header_names[2] = { foo.h, mydir/myinc.h };
                 0, NULL, // num_devices & device_list
                 NULL,    // compile_options
                 2,       // num_input_headers
                 NULL, NULL); // pfn_notify & user_data

clCompileProgram returns CL_​SUCCESS if the function is executed successfully. Otherwise, it returns one of the following errors:

  • CL_​INVALID_​PROGRAM if program is not a valid program object.

  • CL_​INVALID_​VALUE if device_list is NULL and num_devices is greater than zero, or if device_list is not NULL and num_devices is zero.

  • CL_​INVALID_​VALUE if num_input_headers is zero and header_include_names or input_headers are not NULL or if num_input_headers is not zero and header_include_names or input_headers are NULL.

  • CL_​INVALID_​VALUE if pfn_notify is NULL but user_data is not NULL.

  • CL_​INVALID_​DEVICE if device in device_list is not in the list of devices associated with program.

  • CL_​INVALID_​COMPILER_​OPTIONS if the compiler options specified by options are invalid.

  • CL_​INVALID_​OPERATION if the compilation or build of a program executable for any of the devices listed in device_list by a previous call to clCompileProgram or clBuildProgram for program has not completed.

  • CL_​COMPILER_​NOT_​AVAILABLE if a compiler is not available i.e. CL_​DEVICE_​COMPILER_​AVAILABLE specified in the Device Queries table is set to CL_​FALSE.

  • CL_​COMPILE_​PROGRAM_​FAILURE if there is a failure to compile the program source. This error will be returned if clCompileProgram does not return until the compile has completed.

  • CL_​INVALID_​OPERATION if there are kernel objects attached to program.

  • CL_​INVALID_​OPERATION if program has no source or IL available, i.e. it has not been created with clCreateProgramWithSource or clCreateProgramWithIL.

  • CL_​OUT_​OF_​RESOURCES if there is a failure to allocate resources required by the OpenCL implementation on the device.

  • CL_​OUT_​OF_​HOST_​MEMORY if there is a failure to allocate resources required by the OpenCL implementation on the host.

See Also

Document Notes

For more information, see the OpenCL Specification

This page is extracted from the OpenCL Specification. Fixes and changes should be made to the Specification, not directly.

Copyright (c) 2014-2020 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.