c - matrix library: inline vs define -

i'm creating matrix library bunch of function 1 (it's long one):

void matx_multiply(int x, float mat1[], float mat2[], float result[]) {     int row,col,k;      (row=0; row<x; row++) {         for(col=0; col<x; col++){             result[row + col*x]=0.0f;             (k=0; k<x; k++)             {                 result[row + col*x]+=mat1[row + k*x]*mat2[k + col*x];             }         }     } } 

firstly, wonder if it's better change inline function if use ~5 times in program (often in loop), x being known @ compile time.

i think it's better inline it, compiler can decide @ compile time whether want expanded in code or not (depending on optimization parameter). in addition, compiler might optimize loop if knows x (for example, if x=2, may decide unroll loop)

more importantly, want add set of functions:

#define mat2_multiply(m1,m2,res) matx_multiply(2,m1,m2,res) #define mat3_multiply(m1,m2,res) matx_multiply(3,m1,m2,res) ... 

or

static inline void mat2_multiply(float mat1[static 2],                                  float mat2[static 2],                                  float result[static 2]) {     matx_multiply(2,mat1,mat2,result); } ... 

or creating function (but create function call nothing)

• one way more concise , expanded (it verify if mat1 , mat2 array of float anyway)
• the second way more secure, verify length of array, it's less concies , may not expanded...

what do, , want matrix library ?

i want library fast (for opengl app), small , easy use.

use inline keyword. there several disadvantages if use preprocessor develop function-like macros:

• no type safety checking
• no sanity checking
• bad debug
• bad readability
• expressions passed macros can evaluated more once