Question

在objective-c中，我可以调用代码来获取回溯 void* callstack[128]; int frames = backtrace(callstack, 128); char **strs = backtrace_symbols(callstack, frames); 按导入#include <execinfo.h>

但是在swift中，如何调用backtrace和backtrace_symbols，我无法找到execinfo文件

Answer 1

在Swift 3中，您只需使用即可打印堆栈回溯（来自How to print call stack in Swift?）：

for symbol in Thread.callStackSymbols {
    print(symbol)
}

但是如果你很好奇如何将C代码翻译成Swift：首先添加

#include <execinfo.h>

到桥接头文件以生成backtrace()函数可用。然后请注意void *对应在Swift中UnsafeMutableRawPointer?，你差不多完成了：

var callstack = [UnsafeMutableRawPointer?](repeating: nil, count: 128)
let frames = backtrace(&callstack, Int32(callstack.count))
if let symbols = backtrace_symbols(&callstack, frames) {
    for frame in 0..<Int(frames) where symbols[frame] != nil {
        let symbol = String(cString: symbols[frame]!)
        print(symbol)
    }
    free(symbols)
}

Answer 2


@_silgen_name("backtrace")
internal func swift_backtrace(_ callstacks: UnsafeMutableRawPointer, _ counts: Int) -> Int

@_silgen_name("backtrace_symbols")
internal func swift_backtrace_symbols(_ callstacks: UnsafeRawPointer, _ counts: Int) -> UnsafeMutablePointer<UnsafePointer<CChar>>?


var callstack = [UnsafeMutableRawPointer?](repeating: nil, count: 128)
let frames = swift_backtrace(&callstack, callstack.count)

if let symbols = swift_backtrace_symbols(&callstack, frames) {
    for frame in 0..<frames {
        let symbol = String(cString: symbols[frame])
        print(symbol)
    }
    
    free(symbols)
}

如何在swift中调用backtrace_symbols（）

2 个答案: