Thank you Ian and Jake for the response. Sure Ian, will go through it. Thanks, Nitish
On Thu, Mar 19, 2020 at 11:11 PM Ian Lance Taylor <i...@golang.org> wrote: > It might help to read > https://golang.org/cmd/go/#hdr-Package_lists_and_patterns, including > the paragraph starting "As a special case, if the package list is a > list of .go files from a single directory,...." > > Ian > > On Thu, Mar 19, 2020 at 8:59 AM Jake Montgomery <jake6...@gmail.com> > wrote: > > > > > > > > On Thursday, March 19, 2020 at 10:21:31 AM UTC-4, Nitish Saboo wrote: > >> > >> Hi Jake, > >> > >> Is there some reason that you want, or need, to be using go build this > way, by specifying files? Or is it just curiosity about how the tools work? > >> >>There is no particular reason to use go build by specifying the > files. I was trying different ways to compile the project and ended up with > this scenario. > >> I am curious to know the reason for this. > >> > >> The typical way to use go build is to build without specifying > individual files. If you are using CGO, I would certainly recommend that > you do it by building as a package, just to keep things simple. Not that > CGO is ever simple. > >> >> I will try compiling the package without specifying the individual > files. > > > > > > Right, as I said, this is the standard way. You should always build the > package this way, unless you have a specific use case that requires > compiling a single file. > > > >> But the following case works all fine whether we pass the individual > file or not.: > > > > > > The reason that works is because the package you are building only > contains one file, 'main.go'. The other files are actually in different > packages, so they are pulled in by import. So `go build -v - x` builds the > package `nitish`, which only contains one file, `main.go`. Since the > package name is `nitish` you get an executable named `nitish`. `go build -v > - x main.go` is a special use of the tool. I mostly use it for quick code > tests, when the playground will not suffice, or for using go to write quick > scripts. It will not build the package `nitish`, instead it will build only > the single file, and produce an executable named after the file, in this > case `main.exe`. Since the `nitish` package only contains one file, the > result is otherwise the same (AFAIK). > > > > Hope this has some useful information. > >> > >> > >> Case 1 > >> ---------- > >> > >> I have a project called 'nitish' where the folder structure looks like > the following: > >> > >> nitish > >> main.go > >> util > >> util.go > >> lib > >> node.c > >> node.h > >> a.go > >> > >> When I try compiling this project in the following ways: > >> > >> 1) go build -v - x > >> > >> >> This creates a binary called 'nitish' > >> > >> 2) go build -v - x main.go > >> > >> >> This creates a binary called 'main' > >> > >> ldd output of both the binaries is the same. > >> > >> Thanks, > >> Nitish > >> > >> > >> On Thu, Mar 19, 2020 at 7:18 PM Jake Montgomery <jake...@gmail.com> > wrote: > >>> > >>> Nitish, > >>> > >>> Is there some reason that you want, or need, to be using go build this > way, by specifying files? Or is it just curiosity about how the tools work? > >>> The typical way to use go build is to build without specifying > individual files. If you are using CGO, I would certainly recommend that > you do it by building as a package, just to keep things simple. Not that > CGO is ever simple. > >>> > >>> > >>> On Wednesday, March 18, 2020 at 10:27:19 AM UTC-4, Nitish Saboo wrote: > >>>> > >>>> Hi Gregor, > >>>> > >>>> Do you mean like this 'go build -v -x main.go node.c' ? But it does > not compile and gives the following output: > >>>> > >>>> WORK=/tmp/go-build714119815 > >>>> named files must be .go files > >>>> > >>>> Thanks, > >>>> Nitish > >>>> > >>>> On Wed, Mar 18, 2020 at 7:44 PM Gregor Best <be...@pferdewetten.de> > wrote: > >>>>> > >>>>> Hi, > >>>>> > >>>>> it looks like my initial reply wasn't entirely correct. It should > build if you pass in both the `.go` file and the `.c` file. > >>>>> > >>>>> On 18.03.20 15:02, Nitish Saboo wrote: > >>>>> > >>>>> Hi Gregor, > >>>>> > >>>>> nitish > >>>>> main.go > >>>>> node.c > >>>>> node.h > >>>>> > >>>>> I compiled using 'go build -v -x main.go' > >>>>> But if my cgo directive is defined in main.go, this should have > compiled successfully..right? But it fails with the following whereas 'go > build -v -x' works fine. > >>>>> > >>>>> /tmp/go-build439591561/b001/_x002.o: In function > `_cgo_5637ad3d75e4_Cfunc_load_pattern_db': > >>>>> /tmp/go-build/cgo-gcc-prolog:86: undefined reference to > `load_pattern_db' > >>>>> collect2: error: ld returned 1 exit status > >>>>> > >>>>> package main > >>>>> > >>>>> //#include <stdlib.h> > >>>>> //#include "node.h" > >>>>> import "C" > >>>>> import ( > >>>>> "fmt" > >>>>> _ "fmt" > >>>>> "os" > >>>>> "path" > >>>>> "unsafe" > >>>>> ) > >>>>> > >>>>> Please let me know what am I missing here? > >>>>> > >>>>> Thanks, > >>>>> Nitish > >>>>> > >>>>> On Wed, Mar 18, 2020 at 7:20 PM Nitish Saboo <nitish...@gmail.com> > wrote: > >>>>>> > >>>>>> Hi Gregor, > >>>>>> > >>>>>> Got your point.Thank you for your response. > >>>>>> That explains why the binaries have different names post > compilation. > >>>>>> > >>>>>> Thanks, > >>>>>> Nitish > >>>>>> > >>>>>> > >>>>>> On Wed, Mar 18, 2020 at 7:06 PM Gregor Best <be...@pferdewetten.de> > wrote: > >>>>>>> > >>>>>>> Hi, > >>>>>>> > >>>>>>> In both `go build main.go`-examples, you tell the compiler to > _only_ build `main.go`. > >>>>>>> > >>>>>>> In your first example, `main.go` probably imports both `util` and > `lib` (you might want to give them less generic names by the way). The go > compiler thus knows "to build `main.go`, I need to build both `util` and > `lib` and link them in". > >>>>>>> > >>>>>>> In the second example, it has no way of knowing where > `load_pattern_db` comes from, since you didn't tell it to compile a file > that defines that function. > >>>>>>> > >>>>>>> The examples where you omit the `main.go` tell the compiler "build > the package in this directory", which includes all `.go`-files in the > directory. `node.c` and `node.h` are likely built because of `cgo` > directives in `a.go`. > >>>>>>> > >>>>>>> The compiler and linker did exactly as you told them to. > >>>>>>> > >>>>>>> On 18.03.20 14:17, Nitish Saboo wrote: > >>>>>>> > >>>>>>> Hi, > >>>>>>> > >>>>>>> Case 1 > >>>>>>> ---------- > >>>>>>> > >>>>>>> I have a project called 'nitish' where the folder structure looks > like the following: > >>>>>>> > >>>>>>> nitish > >>>>>>> main.go > >>>>>>> util > >>>>>>> util.go > >>>>>>> lib > >>>>>>> node.c > >>>>>>> node.h > >>>>>>> a.go > >>>>>>> > >>>>>>> When I try compiling this project in the following ways: > >>>>>>> > >>>>>>> 1) go build -v - x > >>>>>>> > >>>>>>> >> This creates a binary called 'nitish' > >>>>>>> > >>>>>>> 2) go build -v - x main.go > >>>>>>> > >>>>>>> >> This creates a binary called 'main' > >>>>>>> > >>>>>>> ldd output of both the binaries is the same. > >>>>>>> > >>>>>>> > >>>>>>> Case 2 > >>>>>>> ---------- > >>>>>>> > >>>>>>> Now, when I restructure the project 'nitish' in the following > manner: > >>>>>>> > >>>>>>> nitish > >>>>>>> main.go > >>>>>>> util.go > >>>>>>> node.c > >>>>>>> node.h > >>>>>>> a.go > >>>>>>> > >>>>>>> When I try compiling this project in the following ways: > >>>>>>> > >>>>>>> 1) go build -v - x > >>>>>>> > >>>>>>> >> This creates a binary called 'nitish' > >>>>>>> > >>>>>>> 2) go build -v - x main.go > >>>>>>> > >>>>>>> >> This error out with the following: > >>>>>>> > >>>>>>> /tmp/go-build074530518/b001/_x002.o: In function > `_cgo_8eab385aa676_Cfunc_load_pattern_db': > >>>>>>> /tmp/go-build/cgo-gcc-prolog:86: undefined reference to > `load_pattern_db' > >>>>>>> collect2: error: ld returned 1 exit status > >>>>>>> > >>>>>>> > >>>>>>> 1) In Case 1, why the binaries are created with different names > though both the binaries have the same 'ldd output' and work the same > manner? > >>>>>>> > >>>>>>> 2) Why we see an error with the command 'go build -v - x main.go' > in Case 2 but not in Case 1? > >>>>>>> > >>>>>>> Thanks, > >>>>>>> Nitish > >>>>>>> > >>>>>>> -- > >>>>>>> You received this message because you are subscribed to the Google > Groups "golang-nuts" group. > >>>>>>> To unsubscribe from this group and stop receiving emails from it, > send an email to golan...@googlegroups.com. > >>>>>>> To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/CALjMrq6gpXPbED%2BK2xiOKYvRg08FZwkjoPSUaGg%3DFu5hKP-%2BKQ%40mail.gmail.com > . > >>>>>>> > >>>>>>> -- > >>>>>>> -- > >>>>>>> Gregor Best > >>>>>>> be...@pferdewetten.de > >>>>>>> > >>>>>>> -- > >>>>>>> You received this message because you are subscribed to the Google > Groups "golang-nuts" group. > >>>>>>> To unsubscribe from this group and stop receiving emails from it, > send an email to golan...@googlegroups.com. > >>>>>>> To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/d23423e6-f204-8e63-436b-aa3730013392%40pferdewetten.de > . > >>>>> > >>>>> -- > >>>>> -- > >>>>> Gregor Best > >>>>> be...@pferdewetten.de > >>> > >>> -- > >>> You received this message because you are subscribed to the Google > Groups "golang-nuts" group. > >>> To unsubscribe from this group and stop receiving emails from it, send > an email to golan...@googlegroups.com. > >>> To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/cfddeb60-03af-4f87-a6a8-74f76fb069a5%40googlegroups.com > . > > > > -- > > You received this message because you are subscribed to the Google > Groups "golang-nuts" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to golang-nuts+unsubscr...@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/a0d2fca4-951d-4661-bf08-8010d13bd48b%40googlegroups.com > . > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/CAOyqgcX5tMbQ-r1zxNkjp6pM0nh0UY50jBZSesgHS54OmZJGtw%40mail.gmail.com > . > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. 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