Documentation>C API
generic.c File Reference

Generic - Definition. More...

#include "generic.h"
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <math.h>
#include <Windows.h>
#include <unistd.h>


VlState * vl_get_state (void)
 Return VLFeat global state. More...
VlThreadState * vl_get_thread_specific_state (void)
 Get VLFeat thread state. More...
static void vl_lock_state (void)
 Lock VLFeat state. More...
static void vl_unlock_state (void)
 Unlock VLFeat state. More...
static VlThreadState * vl_thread_specific_state_new (void)
 Construct a new thread state object. More...
static void vl_thread_specific_state_delete (VlThreadState *self)
 Delete a thread state structure. More...
char const * vl_get_version_string ()
 Get VLFeat version string. More...
char * vl_configuration_to_string_copy ()
 Get VLFeat configuration string. More...
static int do_nothing_printf (char const *format,...)
 A printf that does not do anything. More...
vl_size vl_get_num_cpus (void)
 Get the number of CPU cores of the host. More...
void vl_set_simd_enabled (vl_bool x)
 Toggle usage of SIMD instructions. More...
vl_bool vl_get_simd_enabled (void)
 Are SIMD instructons enabled? More...
vl_bool vl_cpu_has_avx (void)
 Check for AVX instruction set. More...
vl_bool vl_cpu_has_sse3 (void)
 Check for SSE3 instruction set. More...
vl_bool vl_cpu_has_sse2 (void)
 Check for SSE2 instruction set. More...
vl_size vl_get_thread_limit (void)
 Get the number of computational threads available to the application. More...
vl_size vl_get_max_threads (void)
 Get the maximum number of computational threads used by VLFeat. More...
void vl_set_num_threads (vl_size numThreads)
 Set the maximum number of threads used by VLFeat. More...
int vl_set_last_error (int error, char const *errorMessage,...)
 Set last VLFeat error. More...
int vl_get_last_error (void)
 Get the code of the last error. More...
char const * vl_get_last_error_message (void)
 Get the last error message. More...
void vl_set_alloc_func (void *(*malloc_func)(size_t), void *(*realloc_func)(void *, size_t), void *(*calloc_func)(size_t, size_t), void(*free_func)(void *))
 Set memory allocation functions. More...
void * vl_malloc (size_t n)
 Allocate a memory block. More...
void * vl_realloc (void *ptr, size_t n)
 Reallocate a memory block. More...
void * vl_calloc (size_t n, size_t size)
 Free and clear a memory block. More...
void vl_free (void *ptr)
 Free a memory block. More...
void vl_set_printf_func (printf_func_t printf_func)
 Set the printf function. More...
printf_func_t vl_get_printf_func (void)
 Get the printf function. More...
double vl_get_cpu_time ()
 Get processor time. More...
void vl_tic (void)
 Reset processor time reference The function resets VLFeat TIC/TOC time reference. There is one such reference per thread. More...
double vl_toc (void)
 Get elapsed time since tic. More...
VlRandvl_get_rand (void)
 Get the default random number generator. More...
static void vl_constructor (void)
 Initialize VLFeat state. More...
static void vl_destructor ()
 Destruct VLFeat. More...

Detailed Description

Andrea Vedaldi

Function Documentation

static int do_nothing_printf ( char const *  format,
void* vl_calloc ( size_t  n,
size_t  size 
nnumber of items to allocate.
sizesize in bytes of an item.
pointer to the new block.

This function allocates and clears a memory block. The synopsis is the same as the POSIX calloc function.

char* vl_configuration_to_string_copy ( void  )
a new configuration string.

The function returns a new string containing a human readable description of the library configuration.

static void vl_constructor ( void  )
vl_bool vl_cpu_has_avx ( void  )
true if AVX is present.
vl_bool vl_cpu_has_sse2 ( void  )
true if SSE2 is present.
vl_bool vl_cpu_has_sse3 ( void  )
true if SSE3 is present.
static void vl_destructor ( )
void vl_free ( void *  ptr)
ptrpointer to the memory block.

This function frees a memory block allocated by vl_malloc, vl_calloc, or vl_realloc. The synopsis is the same as the POSIX malloc function.

double vl_get_cpu_time ( void  )
processor time in seconds.
See also
vl_tic, vl_toc
int vl_get_last_error ( void  )
error code.
See also
char const* vl_get_last_error_message ( void  )
pointer to the error message.
See also
vl_size vl_get_max_threads ( void  )
number of threads.

This function returns the maximum number of thread used by VLFeat. VLFeat will try to use this number of computational threads and never exceed it.

This is similar to the OpenMP function omp_get_max_threads(); however, it reads a parameter private to VLFeat which is independent of the value used by the OpenMP library.

If VLFeat was compiled without OpenMP support, this function returns 1.

See also
vl_set_num_threads(), Parallel computations
vl_size vl_get_num_cpus ( void  )
number of CPU cores.
printf_func_t vl_get_printf_func ( void  )
printf_func pointer to the printf implementation.
See also
VlRand* vl_get_rand ( void  )
random number generator.

The function returns a pointer to the default random number generator. There is one such generator per thread.

vl_bool vl_get_simd_enabled ( void  )
true if SIMD instructions are enabled.
VlState * vl_get_state ( void  )

The function returns a pointer to VLFeat global state.

pointer to the global state structure.
vl_size vl_get_thread_limit ( void  )
number of threads.

This function wraps the OpenMP function omp_get_thread_limit(). If VLFeat was compiled without OpenMP support, this function returns 1. If VLFeat was compiled with OpenMP prior to version 3.0 (2008/05), it returns 0.

See also
Parallel computations
VlThreadState * vl_get_thread_specific_state ( void  )
pointer to the thread state structure.

The function returns a pointer to VLFeat thread state.

char const* vl_get_version_string ( void  )
the library version string.
static void vl_lock_state ( void  )

The function locks VLFeat global state mutex.

The mutex is recursive: locking multiple times from the same thread is a valid operations, but requires an equivalent number of calls to vl_unlock_state.

See also
void* vl_malloc ( size_t  n)
nsize in bytes of the new block.
pointer to the allocated block.

This function allocates a memory block of the specified size. The synopsis is the same as the POSIX malloc function.

void* vl_realloc ( void *  ptr,
size_t  n 
ptrpointer to a memory block previously allocated.
nsize in bytes of the new block.
pointer to the new block.

This function reallocates a memory block to change its size. The synopsis is the same as the POSIX realloc function.

void vl_set_alloc_func ( void *(*)(size_t)  malloc_func,
void *(*)(void *, size_t)  realloc_func,
void *(*)(size_t, size_t)  calloc_func,
void(*)(void *)  free_func 
malloc_funcpointer to malloc.
realloc_funcpointer to realloc.
calloc_funcpointer to calloc.
free_funcpointer to free.
int vl_set_last_error ( int  error,
char const *  errorMessage,
errorerror code.
errorMessageerror message format string.
...format string arguments.
error code.

The function sets the code and optionally the error message of the last encountered error. errorMessage is the message format. It uses the printf convention and is followed by the format arguments. The maximum length of the error message is given by VL_ERR_MSG_LEN (longer messages are truncated).

Passing NULL as errorMessage sets the error message to the empty string.

void vl_set_num_threads ( vl_size  numThreads)
numThreadsnumber of threads to use.

This function sets the maximum number of computational threads that will be used by VLFeat. VLFeat may in practice use fewer threads (for example because numThreads is larger than the number of computational cores in the host, or because the number of threads exceeds the limit available to the application).

If numThreads is set to 0, then VLFeat sets the number of threads to the OpenMP current maximum, obtained by calling omp_get_max_threads().

This function is similar to omp_set_num_threads() but changes a parameter internal to VLFeat rather than affecting OpenMP global state.

If VLFeat was compiled without, this function does nothing.

See also
vl_get_max_threads(), Parallel computations
void vl_set_printf_func ( printf_func_t  printf_func)
printf_funcpointer to a printf implementation. Set print_func to NULL to disable printf.
vl_set_simd_enabled ( vl_bool  x)
xtrue if SIMD instructions are used.

Notice that SIMD instructions are used only if the CPU model supports them. Note also that data alignment may restrict the use of such instructions.

See also
vl_cpu_has_sse2(), vl_cpu_has_sse3(), etc.
static void vl_thread_specific_state_delete ( VlThreadState *  self)
selfthread state object.
static VlThreadState * vl_thread_specific_state_new ( void  )
new state structure.
void vl_tic ( void  )
double vl_toc ( void  )
elapsed time in seconds.

The function returns the processor time elapsed since vl_tic was called last.

In multi-threaded applications, there is an independent timer for each execution thread.
On UNIX, this function uses the clock() system call. On Windows, it uses the QueryPerformanceCounter() system call, which is more accurate than clock() on this platform.
static void vl_unlock_state ( void  )

The function unlocks VLFeat global state mutex.

See also