pragma solidity ^0.4.21; contract Test1 { function add(int a, int b) returns(string){ //Simply add the two arguments and return return "Qmrwokdkeoiudkeooiskelpdislpeosj;sd[opek;s[pkfe,;soeipsoekf;sodfpsoe,mfoskfesktgfetg"; } } contract Test2 { Test1 test1; function Test2(){ //Constructor function test1 = new Test1(); //Create new "Test1" function } function test(string a, string b) constant returns (string c){ address addr = address(test1); //Place the test1 address on the stack bytes4 sig = bytes4(sha3("add(int256,int256)")); //Function signature assembly { let x := mload(0x40) //Find empty storage location using "free memory pointer" mstore(x,sig) //Place signature at begining of empty storage mstore(add(x,0x04),a) //Place first argument directly next to signature mstore(add(x,0x24),b) //Place second argument next to first, padded to 32 bytes let success := call( //This is the critical change (Pop the top stack value) 5000, //5k gas addr, //To addr 0, //No value x, //Inputs are stored at location x 0x44, //Inputs are 68 bytes long x, //Store output over input (saves space) 0x20) //Outputs are 32 bytes long c := mload(x) //Assign output value to c mstore(0x40,add(x,0x44)) // Set storage pointer to empty space } } } but c is empty string
