1 /* ----------------------------------------------------------------------------- 2 * typemaps.i 3 * 4 * Pointer handling 5 * These mappings provide support for input/output arguments and common 6 * uses for C/C++ pointers. 7 * ----------------------------------------------------------------------------- */ 8 9 // INPUT typemaps. 10 // These remap a C pointer to be an "INPUT" value which is passed by value 11 // instead of reference. 12 13 /* 14 The following methods can be applied to turn a pointer into a simple 15 "input" value. That is, instead of passing a pointer to an object, 16 you would use a real value instead. 17 18 int *INPUT 19 short *INPUT 20 long *INPUT 21 long long *INPUT 22 unsigned int *INPUT 23 unsigned short *INPUT 24 unsigned long *INPUT 25 unsigned long long *INPUT 26 unsigned char *INPUT 27 bool *INPUT 28 float *INPUT 29 double *INPUT 30 31 To use these, suppose you had a C function like this : 32 33 double fadd(double *a, double *b) { 34 return *a+*b; 35 } 36 37 You could wrap it with SWIG as follows : 38 39 %include <typemaps.i> 40 double fadd(double *INPUT, double *INPUT); 41 42 or you can use the %apply directive : 43 44 %include <typemaps.i> 45 %apply double *INPUT { double *a, double *b }; 46 double fadd(double *a, double *b); 47 48 */ 49 50 // OUTPUT typemaps. These typemaps are used for parameters that 51 // are output only. The output value is appended to the result as 52 // a list element. 53 54 /* 55 The following methods can be applied to turn a pointer into an "output" 56 value. When calling a function, no input value would be given for 57 a parameter, but an output value would be returned. In the case of 58 multiple output values, they are returned in the form of a Python tuple. 59 60 int *OUTPUT 61 short *OUTPUT 62 long *OUTPUT 63 long long *OUTPUT 64 unsigned int *OUTPUT 65 unsigned short *OUTPUT 66 unsigned long *OUTPUT 67 unsigned long long *OUTPUT 68 unsigned char *OUTPUT 69 bool *OUTPUT 70 float *OUTPUT 71 double *OUTPUT 72 73 For example, suppose you were trying to wrap the modf() function in the 74 C math library which splits x into integral and fractional parts (and 75 returns the integer part in one of its parameters).K: 76 77 double modf(double x, double *ip); 78 79 You could wrap it with SWIG as follows : 80 81 %include <typemaps.i> 82 double modf(double x, double *OUTPUT); 83 84 or you can use the %apply directive : 85 86 %include <typemaps.i> 87 %apply double *OUTPUT { double *ip }; 88 double modf(double x, double *ip); 89 90 The Python output of the function would be a tuple containing both 91 output values. 92 93 */ 94 95 // INOUT 96 // Mappings for an argument that is both an input and output 97 // parameter 98 99 /* 100 The following methods can be applied to make a function parameter both 101 an input and output value. This combines the behavior of both the 102 "INPUT" and "OUTPUT" methods described earlier. Output values are 103 returned in the form of a Python tuple. 104 105 int *INOUT 106 short *INOUT 107 long *INOUT 108 long long *INOUT 109 unsigned int *INOUT 110 unsigned short *INOUT 111 unsigned long *INOUT 112 unsigned long long *INOUT 113 unsigned char *INOUT 114 bool *INOUT 115 float *INOUT 116 double *INOUT 117 118 For example, suppose you were trying to wrap the following function : 119 120 void neg(double *x) { 121 *x = -(*x); 122 } 123 124 You could wrap it with SWIG as follows : 125 126 %include <typemaps.i> 127 void neg(double *INOUT); 128 129 or you can use the %apply directive : 130 131 %include <typemaps.i> 132 %apply double *INOUT { double *x }; 133 void neg(double *x); 134 135 Unlike C, this mapping does not directly modify the input value (since 136 this makes no sense in Python). Rather, the modified input value shows 137 up as the return value of the function. Thus, to apply this function 138 to a Python variable you might do this : 139 140 x = neg(x) 141 142 Note : previous versions of SWIG used the symbol 'BOTH' to mark 143 input/output arguments. This is still supported, but will be slowly 144 phased out in future releases. 145 146 */ 147 148 %include <typemaps/typemaps.swg> 149
