VLFeat - Documentation> C API

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_memalign (size_t n, size_t size)

void vl_free (void *ptr)

Free a memory block. More...

Measuring time

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...

double vl_get_cpu_time (void)

Get processor time. More...

Type identifiers for atomic data types

#define VL_TYPE_FLOAT 1

#define VL_TYPE_DOUBLE 2

#define VL_TYPE_INT8 3

#define VL_TYPE_UINT8 4

#define VL_TYPE_INT16 5

#define VL_TYPE_UINT16 6

#define VL_TYPE_INT32 7

#define VL_TYPE_UINT32 8

#define VL_TYPE_INT64 9

#define VL_TYPE_UINT64 10

typedef vl_uint32 vl_type

char const * vl_get_type_name (vl_type type)

Get the name of a data type. More...

vl_size vl_get_type_size (vl_type type)

Get data type size. More...

Error handling

#define VL_ERR_OK 0

#define VL_ERR_OVERFLOW 1

#define VL_ERR_ALLOC 2

#define VL_ERR_BAD_ARG 3

#define VL_ERR_IO 4

#define VL_ERR_EOF 5

#define VL_ERR_NO_MORE 5

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...

int vl_set_last_error (int error, char const *errorMessage,...)

Set last VLFeat error. More...

Logging

#define VL_PRINTF (*vl_get_printf_func())

Call user-customizable printf function. More...

#define VL_PRINT (*vl_get_printf_func())

Same as VL_PRINTF (legacy code)

typedef int(* printf_func_t) (char const *format,...)

Customizable printf function pointer type.

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...

Detailed Description

Author: Andrea Vedaldi

Macro Definition Documentation

◆ VL_ERR_ALLOC

#define VL_ERR_ALLOC 2

Resource allocation error

◆ VL_ERR_BAD_ARG

#define VL_ERR_BAD_ARG 3

Bad argument or illegal data error

◆ VL_ERR_EOF

#define VL_ERR_EOF 5

End-of-file or end-of-sequence error

◆ VL_ERR_IO

#define VL_ERR_IO 4

Input/output error

◆ VL_ERR_NO_MORE

#define VL_ERR_NO_MORE 5

End-of-sequence

Deprecated:

◆ VL_ERR_OK

#define VL_ERR_OK 0

No error

◆ VL_ERR_OVERFLOW

#define VL_ERR_OVERFLOW 1

Buffer overflow error

◆ VL_MAX

#define VL_MAX ( x,

) (((x)>(y))?(x):(y))

Parameters: x value.

y value.

Returns: the maximum of x and y.

◆ VL_MIN

#define VL_MIN ( x,

) (((x)<(y))?(x):(y))

Parameters: x value

y value

Returns: the minimum of x and y.

◆ VL_PRINTF

#define VL_PRINTF (*vl_get_printf_func())

The function calls the user customizable printf.

◆ VL_SHIFT_LEFT

#define VL_SHIFT_LEFT ( x,

) (((n)>=0)?((x)<<(n)):((x)>>-(n)))

Parameters: x value.

n number of shift positions.

Returns: x << n . The macro is equivalent to the builtin << operator, but it supports negative shifts too.

◆ VL_TYPE_DOUBLE

#define VL_TYPE_DOUBLE 2

double type

◆ VL_TYPE_FLOAT

#define VL_TYPE_FLOAT 1

float type

◆ VL_TYPE_INT16

#define VL_TYPE_INT16 5

vl_int16 type

◆ VL_TYPE_INT32

#define VL_TYPE_INT32 7

vl_int32 type

◆ VL_TYPE_INT64

#define VL_TYPE_INT64 9

vl_int64 type

◆ VL_TYPE_INT8

#define VL_TYPE_INT8 3

vl_int8 type

◆ VL_TYPE_UINT16

#define VL_TYPE_UINT16 6

vl_uint16 type

◆ VL_TYPE_UINT32

#define VL_TYPE_UINT32 8

vl_uint32 type

◆ VL_TYPE_UINT64

#define VL_TYPE_UINT64 10

vl_uint64 type

◆ VL_TYPE_UINT8

#define VL_TYPE_UINT8 4

vl_uint8 type

Function Documentation

◆ vl_calloc()

void* vl_calloc ( size_t n,

size_t size

)

Parameters: n number of items to allocate.

size size in bytes of an item.

Returns: pointer to the new block.

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

◆ vl_configuration_to_string_copy()

char* vl_configuration_to_string_copy ( void )

Returns: a new configuration string.

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

◆ vl_cpu_has_avx()

vl_bool vl_cpu_has_avx ( void )

Returns: true if AVX is present.

◆ vl_cpu_has_sse2()

vl_bool vl_cpu_has_sse2 ( void )

Returns: true if SSE2 is present.

◆ vl_cpu_has_sse3()

vl_bool vl_cpu_has_sse3 ( void )

Returns: true if SSE3 is present.

◆ vl_free()

void vl_free ( void * ptr )

Parameters: ptr pointer 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.

◆ vl_get_cpu_time()

double vl_get_cpu_time ( void )

Returns: processor time in seconds.

See also: vl_tic, vl_toc

◆ vl_get_last_error()

int vl_get_last_error ( void )

Returns: error code.

See also: vl_get_last_error_message.

◆ vl_get_last_error_message()

char const* vl_get_last_error_message ( void )

Returns: pointer to the error message.

See also: vl_get_last_error.

◆ vl_get_max_threads()

vl_size vl_get_max_threads ( void )

Returns: 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_get_num_cpus()

vl_size vl_get_num_cpus ( void )

Returns: number of CPU cores.

◆ vl_get_printf_func()

printf_func_t vl_get_printf_func ( void )

Returns: printf_func pointer to the printf implementation.

See also: vl_set_printf_func.

◆ vl_get_rand()

VlRand* vl_get_rand ( void )

Returns: random number generator.

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

◆ vl_get_simd_enabled()

vl_bool vl_get_simd_enabled ( void )

Returns: true if SIMD instructions are enabled.

◆ vl_get_thread_limit()

vl_size vl_get_thread_limit ( void )

Returns: 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

◆ vl_get_type_name()

char const* vl_get_type_name ( vl_type type )

inline

Parameters: type data type.

Returns: data name of the data type.

type is one of VL_TYPE_FLOAT, VL_TYPE_DOUBLE, VL_TYPE_INT8, VL_TYPE_INT16, VL_TYPE_INT32, VL_TYPE_INT64, VL_TYPE_UINT8, VL_TYPE_UINT16, VL_TYPE_UINT32, VL_TYPE_UINT64.

◆ vl_get_type_size()

vl_size vl_get_type_size ( vl_type type )

inline

Parameters: type data type.

Returns: size (in byte)

type is one of VL_TYPE_FLOAT, VL_TYPE_DOUBLE, VL_TYPE_INT8, VL_TYPE_INT16, VL_TYPE_INT32, VL_TYPE_INT64, VL_TYPE_UINT8, VL_TYPE_UINT16, VL_TYPE_UINT32, VL_TYPE_UINT64.

◆ vl_get_version_string()

char const* vl_get_version_string ( void )

Returns: the library version string.

◆ vl_malloc()

void* vl_malloc ( size_t n )

Parameters: n size in bytes of the new block.

Returns: 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.

◆ vl_realloc()

void* vl_realloc ( void * ptr,

size_t n

)

Parameters: ptr pointer to a memory block previously allocated.

n size in bytes of the new block.

Returns: 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.

◆ vl_set_alloc_func()

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

)

Parameters: malloc_func pointer to malloc.

realloc_func pointer to realloc.

calloc_func pointer to calloc.

free_func pointer to free.

◆ vl_set_last_error()

int vl_set_last_error ( int error,

char const * errorMessage,

...

)

Parameters: error error code.

errorMessage error message format string.

... format string arguments.

Returns: 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.

◆ vl_set_num_threads()

void vl_set_num_threads ( vl_size numThreads )

Parameters: numThreads number 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

◆ vl_set_printf_func()

void vl_set_printf_func ( printf_func_t printf_func )

Parameters: printf_func pointer to a printf implementation. Set print_func to NULL to disable printf.

◆ vl_set_simd_enabled()

void vl_set_simd_enabled ( vl_bool x )

Parameters: x true 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.

◆ vl_tic()

void vl_tic ( void )

See also: vl_get_cpu_time, vl_toc.

◆ vl_toc()

double vl_toc ( void )

Returns: elapsed time in seconds.

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

Remarks: 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.

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Macros

Functions