12.4.8 Foreign language wrapper support functions

In addition to the functions described in section 12.4.4.2, there is a family of functions that is used for automatic generation of wrapper functions, for example using the Prolog library library(qpforeign) that provides a Quintus/SICStus compatible foreign language interface.

The PL_cvt_i_*() family of functions is suitable for use with a _Generic selector or C++ overloading.^{222_Generic needs to take into account that there's no bool type in C but there is in C++. An overloaded integer() method is provided in the C++ interface.}

Note that the documentation on this API is incomplete. Also note that many of these functions are equivalent to the PL_get_*_ex() functions described in section 12.4.7.

bool PL_cvt_i_bool(term_t p, int *c)

Equivalent to PL_get_bool_ex(). Note that the pointer is to an int because C has no bool type. The return value is either 0 or 1.

bool PL_cvt_i_char(term_t p, char *c)

bool PL_cvt_i_schar(term_t p, signed char *c)

bool PL_cvt_i_uchar(term_t p, unsigned char *c)

bool PL_cvt_i_short(term_t p, short *s)

bool PL_cvt_i_ushort(term_t p, unsigned short *s)

bool PL_cvt_i_int(term_t p, int *c)

bool PL_cvt_i_uint(term_t p, unsigned int *c)

bool PL_cvt_i_long(term_t p, long *c)

bool PL_cvt_i_ulong(term_t p, unsigned long *c)

bool PL_cvt_i_llong(term_t p, long long *c)

bool PL_cvt_i_ullong(term_t p, unsigned long long *c)

bool PL_cvt_i_int32(term_t p, int32_t *c)

bool PL_cvt_i_uint32(term_t p, uint32_t *c)

bool PL_cvt_i_int64(term_t p, int64_t *c)

bool PL_cvt_i_uint64(term_t p, uint64_t *c)

bool PL_cvt_i_size_t(term_t p, size_t *c)

Convert a Prolog integer into a C integer of the specified size. Generate an exception and return FALSE if the conversion is impossible because the Prolog term is not an integer or the C type cannot represent the value of the Prolog integer.